Future Airplanes Will Fly on Twistable Wings | Hacker News Reader

Future Airplanes Will Fly on Twistable Wings

spectrum.ieee.org

70 pointsprostoalex29 comments

Full circle to the Wright Flyer then:

https://en.wikipedia.org/wiki/Wright_Flyer

That's what I thought too.

Don't forget birds! They have the first known wing-warping design. :)

As a follow-up a somewhat readable copy of the wing-warping patent filed by "O & W Wright" is here: https://www.google.com/patents/US821393

Always a bit careful when reading an article written by a researcher who is very excited about his own innovations. I take the optimism with a grain of salt.

Same; as I was reading it and the author started talking about himself working on it I had a bunch of red flags smack me in the face. Sure, be excited about your stuff and it may be completely legit but when someone publishes about their own work outside of a research paper that includes data it makes me think they're fund raising and trying to sell me on all of the extreme possibilities.

F/A-18 Active Aeroelastic Wing [2006]:

https://www.nasa.gov/centers/armstrong/news/FactSheets/FS-06...

https://en.wikipedia.org/wiki/Boeing_X-53_Active_Aeroelastic...

I was following a giant wind generator blade down the highway on a windy day. Seen from the back (following the rig) I saw the thing twisting and bobbing constantly. Its like it was made of rubber!

Not an airplane wing, I know, but similar.

Anything when made long enough will flex like that. Imagine that those blades are made of carbon fiber, resin and are designed for maximum stiffness!

Fortunately the loading of those blades is relatively constant, the majority of the load will come at a 90 degree angle to the plane of rotation, the angle at which the leading edge hits the apparent (not the real) wind. That apparent wind has a speed that is a fairly large multiple (7 or so) of the speed of the real wind and the 'flex' that you observe is almost all at right angles to that wind.

In other words: those blades are floppy in the direction where they can afford to be floppy, but extremely stiff along the axis where their main load is. If they wouldn't be the tips would lag behind the hub and they definitely do not do that in any significant amount.

Another good reason to make the blades a bit flexible in their long axis parallel to the tower is that this allows the blades to deal better with tower thump. A blade rigid in that dimension would cause a much sharper rise of the pressure wave of air trapped between the blade and the tower, and this results in a blade that will live that much longer (and a machine that runs quieter).

That is also the reason for the angle at which the nacelle is set, this creates a bit more room at the bottom where the blade flex is at its maximum, it also helps to offset wind-shear.

Also, the shapes are nowadays pre-bent in the opposite direction, so they get more optimal when they are loaded. You can do many things in a wind turbine that would be dangerous in an aircraft.

Airplane wings will already twist and flex to pretty impressive extents, they're much less rigid than one would naively assume. This is dramatically visible during wing loading tests[0]

[0] https://youtu.be/B74_w3Ar9nI?t=78

Even during normal flight the tips of a 747 wing will move 6-7 feet. They're designed to be able to flex three times that distance.

Indeed. You can see this clearly on modern wide-bodies at takeoff if you sit over the wing. The wings droop until the aircraft hits liftoff velocity--at that point the wings lift up and you are wheels up a couple of seconds later. It's close to 10 feet at the tip on a Boeing 777, where the effect seems particularly pronounced.

It's also easy to observe wing movement easily during turbulence. I find it fun to watch but that's probably not to the taste of every passenger. On DC-10s you can also see the engines swinging on their mounts. That is a bit less enjoyable.

The wingtips don't 'lift up', the body drops relative to the wing. Essentially the wing goes from hanging from the body to the body hanging off the wing.

I guess it depends on the frame of reference. The change happens while the plane is still on the runway before lift off.

Like blended wing body configurations, propfan propulsion, "smart" materials with embedded sensors, this is an aerospace technology that has merit and has been studied for decades. It is not any closer to implementation in any commercial aircraft because existing designs work well enough and are far less risky to analyze and test.

what about flapping for thrust next?

I'm ready for ornithopters if you are. And then heighliners.

Holy fuck, that site displays full page ad on top of the page and when you scroll down, it scrolls back up. After certain time you can scroll down.

Let me improve your life a little http://www.printfriendly.com/print/?source=homepage&url=http...

Or a little more still: https://chrome.google.com/webstore/detail/ublock-origin/cjpa...

What about mobile?

I use uBlock Origin on my desktop and AdBlock on my iPhone

Firefox for Android allows extensions, you can use https://addons.mozilla.org/en-US/android/addon/ublock-origin...

If your phone is a rooted Android, you can also use a hostfile that blacklists many ad servers, such as https://adaway.org/

On iOS, "Content Blockers" for Safari can be used for ad blocking, and there is plenty of choice in the App Store.

I don't mind the ad, but the other complaint doesn't seem to be true. You must have clicked on the scroll-to-the top icon.

Blocking all 3rd-party content helps. Even the scripts aren't necessary.

https://i.imgur.com/UuTPQ7t.png

uMatrix and http://someonewhocares.org/hosts/ have completely replaced dedicated adblockers for me.

Well, there are some things that some adblockers do that umatrix doesn't:

Selector-based DOM element removal/hiding and blocking of specific requests by URL instead of by domain

I just hit back when the ads are too obnoxious. It isn't worth it to me.

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